Surfboard with Adjustable and Adaptive Bottom Contours

ABSTRACT

The surfboard disclosed is a structural assembly of a rigid component forming at least the deck and rails, and a pliant component forming at least some portion of the bottom surface, joined to enclose a hollow volume. By means of a user controlled pneumatic adjustment to the hollow volume, a plurality of bottom contour shapes is available to the surfboard.

BACKGROUND OF THE INVENTION Field of the Invention

This invention relates to surfboards for riding waves, and recreational watercraft known as knee-boards, body-boards, windsurf-boards, kite-boards, paddle-boards, stand-up-paddle boards, and the like. Specifically, this invention relates to surfboard bottom contours.

Background Art

A surfboard of the current era is typically shaped to have bottom contours which facilitate a particular intended functionality and “feel.” Generally, a convex roll enables a surfboard to sit down in and displace the water of a wave, while flats or concaves enable a surfboard to lift from and plane upon it. Combinations of these basic forms and additional variations in bottom contours such as “vees,” panels, bellies, concaves, channels, steps, chines, and edges, direct water flow and further influence the ways in which a surfboard will handle.

Surfboards in the art are typically fabricated as rigid laminated surfaces over a foam or hollow core. Rigid surfaces efficiently direct water flow, yet generally delimit the bottom contours of a surfboard to a fixed shape and range of function. These rigid surfaces are generally brittle and subject to pressure dings which can permanently deform bottom contours.

Surfboards are conventionally measured, along with the traditional values of length, width, and thickness, as a volume. The thickness foil dimensions, which typically vary over the length of a surfboard, contribute to a surfboard's specific volume, and so to its buoyancy as well as its flexibility. Generally, a thicker surfboard foil will float more than a thinner one, while a thinner surfboard foil will flex more than a thicker one. Surfboard shapes in the art typically compromise the attributes of float and flex. A specific and fixed volume delimits the range of functionality of a surfboard.

It is desirable that an alternative surfboard be available that is adjustable to a range of bottom contour shapes and volume dimensions.

BRIEF SUMMARY OF THE INVENTION

Accordingly, it is the object of this invention to provide a durable surfboard with bottom contours that are adaptable to a plurality of different shapes. It is another object of this invention to provide a surfboard with a functionally variable volume. The disclosed surfboard is of simple construction, and achieves these objectives by reliable methods of manufacture.

The surfboard is a structural assembly of a rigid shell that forms at least the deck and rails, and a pliant skin that forms at least some portion of the bottom surface. The skin is stretched to a degree of tension sufficient to efficiently direct water flow by spanning remote portions of the shell to which it is connected. A hollow volume is enclosed between the joined shell and skin. The sealed surfboard assembly is vent-able and drain-able and pneumatically adjustable by means of a valve or valves fitted through the shell. Bottom contour shape and thickness foil is modifiable by way of pneumatic adjustments that reshape and further tension the adaptable skin by controlling the extent of its convex distension away from, or concave contraction towards, the underside of the deck. The shape of the underside of the shell, operating as a bottom contour substructure from within the hollow volume of the surfboard assembly, can further influence the contours of the skin that spans it.

One advantage of the disclosed surfboard is that it is adjustable to a plurality of bottom contour shapes, enabling a single surfboard to be adjusted for different conditions and user preference. Another advantage is that its functionally variable volume increases the surfboard's range of buoyancy, accommodating different user weights and abilities. Another advantage it that it it's resilient pliant surface is resistant to pressure dings. Further, a novel “feel” and functionality is realized with the surfboard's adaptive bottom contours.

BRIEF DESCRIPTION OF THE DRAWINGS

In illustrations and embodiments,

FIG. 1 shows a vertical cross-sectional view from the tail of an embodiment.

FIG. 2 shows a perspective view of another embodiment's shell from the left side of the tail

DETAILED DESCRIPTION OF THE INVENTION

A surfboard with adjustable and adaptive bottom contours is here disclosed with reference to drawings of exemplary embodiments. Surfboard shapes are complex combinations of compounding curves that all inform one another. Aspects of surfboard design already known to the art that are applicable to embodiments of the invention disclosed, such as plan shape, rocker curve, rail shape, along with their dimensions and proportionality, are not here described in detail. The illustrations and descriptions throughout this disclosure, along with any statement of materials or dimensions, are provided not to limit this disclosure in any way to these particular embodiments, but are to be interpreted as encompassing any equivalent, variant, or alternative embodiment, without departing from the scope of the appended claims.

FIG. 1 shows an embodiment of the surfboard in a vertical cross-section at its longitudinal center point, as seen from the tail, showing its lateral extension from rail to rail. The surfboard is a structural assembly of a pliant bottom skin 1 joined by an impermeable connection 2 to a rigid upper shell 3. A hollow volume 7 is enclosed within the assembly.

The term “skin,” as claimed, refers to the pliant portion of the surfboard's bottom surface that forms its adaptive bottom contours. The skin is a resilient and impermeable membrane layer that spans remote portions of the shell. As such, the sealed nylon skin of this embodiment is stretched to span the lowermost surfaces of the shell along its rail profiles 4, which extend from nose to tail. Tensioned yet elastic, the skin forms the entire bottom surface of the embodiment and assumes its basic contour shape from the shell, with which it maintains an impermeable connection 2 at its peripheries.

The term “shell,” as claimed, refers to any rigid portion of the surfboard, and forms its basic length, width, and unmodified thickness foil dimensions. As such, the composite foam and fiberglass shell of this embodiment extends longitudinally from a nose to a tail, and laterally from rail to rail, with a domed deck 5 contour and a thinly spaced inversely facing underside 6 contour, inboard of the left and right contiguous rail profiles 4. The rail profiles extend downwardly from the deck's peripheries, forming the surfboard's plan shape with their laterally oriented surfaces and the surfboard's rail rocker curve with their lowermost surfaces. The inboard sections of the rail profiles return upwards into the hollow volume and blend into the underside of the shell. Joined as an integral and impermeable structure, the skin and shell together form the exterior surfaces of the surfboard and enclose a hollow volume.

The term “hollow volume,” as claimed, refers to the sealed air space enclosed between skin and shell that is capable of being positively, negatively, or equally pressurized in relation to the atmospheric pressure surrounding the surfboard. As such, the hollow volume of this embodiment is accessible by a two-way pneumatic valve 8 fitted through the shell, through which ingress or egress and sealing of air within the surfboard can be controlled.

The pneumatic valve 8 enables the user to adjust the bottom contour shape of the surfboard. By controlling an ingress of air through the valve and positively pressurizing the hollow volume, an incrementally adjustable convex bottom contour 10 is produced as the skin is distended outwardly. Alternatively, by controlling an egress of air through the valve and negatively pressurizing the hollow volume, an incrementally adjustable concave bottom contour 11 is produced as the skin is contracted inwardly. The valve can be closed at any point within the range of skin travel to maintain any extent of pneumatically modified bottom contour. These modifications also adjust the thickness foil and buoyancy of the surfboard by increasing or decreasing its volume.

A flat bottom contour 9 is produced by venting the hollow volume 7 to enable an equalization of internal air pressure with that of atmospheric. This is achieved by way of a dedicated vent aperture also installed through the shell, or via the pneumatic valve 8 itself. Resealed as such, the stretched skin is at its least taut and most disposed to a dynamic adaptive contouring when in use. The skin will temporarily recoil from and rebound to its flat bottom contour when subject to the loading forces of water. As the skin flexes and directs water flow over its contours, its pliancy damps water surface chop and vibration, smoothening the “feel” of the user's ride. The skin's adaptive contouring also provides a directional stability to the surfboard. As the skin is temporarily forced into closer contact with the underside of the shell, the surfboard's inboard thickness foil is thinned, and inboard sections of the shell's rail profiles further shape its contours and direct water flow.

The skin is adjustable and adaptive, yielding to both air pressure within the surfboard, and to hydrodynamic forces from its environment in use. The dynamic adaptability of bottom contours is incrementally less pronounced as the skin is adjusted by the user by positively or negatively pressurizing the hollow volume. The greater the convexity or the greater concavity of the adjusted bottom contours, the greater the tautness of the skin. A taut skin will operate to direct water flow over the convexly or concavely adjusted bottom contours, functioning to displace water, or plane upon it, respectively. The skin is resilient, rebounding to its adjusted contour after a more significant point load such as that of an impact, and is resistant to lasting deformations such as creases and pressure dings. The surfboard assembly is durable and lightweight. The surfboard's hollow volume is able to be vented and drained.

FIG. 2 shows a perspective view of another embodiment's shell exploded from its skin, and with the inclusion of a centrally positioned bottom contour substructure 14. The shell's upper-side deck 5 and thinly spaced inverse underside 6 extend in a longitudinal curvature from a nose 17 to a tail 18, and laterally between left and right rail profiles 4, in domed and concave contours respectively.

The term “substructure,” as claimed, refers to any shape or component of the rigid shell's underside that functions to influence the bottom contour shape of the pliant skin from within the hollow volume of the surfboard. As such, the substructure of this embodiment is a single protrusion from the shell's underside 6 running longitudinally straight from nose to tail at the lateral center of the shell. Protruding downwardly to extend lower than the perimeter rail profiles that form the embodiment's rail rocker curves, the substructure delineates a central rocker curve with its lowermost surfaces.

Stretched to the shell, the skin will span between the shell's lowermost surfaces along its rail profiles 4 to which it is joined, and contact the lowermost surfaces of the central substructure 14 along its length. So assembled, the bottom contour of the surfboard is a continuous panel “vee” 21 when the enclosed air pressure is equalized with that of atmospheric, as indicated by the broken line in FIG. 2. A two-way pneumatic valve 8 is fitted through the deck, and the air enclosed on both sides of the central substructure is able to communicate freely by way of a laterally fitted open passageway 19. The user controlled ingress of air into the hollow volume will distend the skin and produce a convexly rolled bottom contour. The user controlled egress of air from the hollow volume will contract the skin towards the shell and produce a double concave “vee” bottom contour. Any adaptive bottom re-contouring in the use of this embodiment will be of a lesser magnitude to that of the embodiment shown in FIG. 1 (the plan shape length and width, and materials of the two embodiments being otherwise equivalent), as the skin spans a smaller unrestricted surface area in its lateral orientation.

Another exemplary embodiment has a similar longitudinally central substructure that protrudes downwardly from the deck's underside, yet remains above the bottom surface of the rail profiles in the surfboard's nose and forward section, and tapers to protrude lower than the rail profiles only through the aft and tail section. In this embodiment, the skin is joined to the shell only at the rails, and is not adhered to the surfaces of the substructure it contacts. The bottom contour produced when the hollow volume is equal in pressure to that of atmospheric, is a flat panel forward blending to a panel “vee” aft. When the skin is distended by the controlled ingress of air, a “belly” forward blends to a rolled “vee” aft. When the skin is contracted by the controlled egress of air, a single concave forward blends to a double concave bottom contour aft.

Referring now to both FIG. 1 and FIG. 2 at once, outboard left-side position 12, inboard left-side position 13, inboard right-side position 15, and outboard right-side position 16, are each location markers for other alternative bottom contour substructure formations protruding from a shell's underside in other embodiments. Illustrated by indicating arrows, their vertical orientations are depicted in FIG. 1, while their longitudinal orientations are depicted in FIG. 2. An embodiment with substructure formations at outboard left-side position 12 and outboard right-side position 16 that protrude lower than, and delineate a similar rocker curve to the shell's rail profiles, has chine bottom contours. An embodiment with substructure formations at inboard left-side position 13 and inboard right-side position 15 that protrude to the same depth as its rail profiles, will have a triple concave bottom contour when the skin is pneumatically contracted.

Various alternatives of substructure layouts at these locations, which produce alternative bottom contour shapes, are possible in other embodiments. Bottom contour substructure formations: extend the complete longitudinal length from nose to tail of the surfboard, or only a portion thereof; protrude below, to the same depth as, or above the lowermost surfaces of the shell's rail profiles; delineate a similar rocker curve to the rail profiles, or a divergent one; are fitted with passageways that allow the communication of air between them, or function without them; are aligned straight from nose to tail, in a parabolic manner to follow the surfboard's template curve, or to curve outwardly towards the surfboard's rails. In consort with the skin's range of pneumatic modification, various combinations of blended bottom contours such as “vees,” panels, “bellies,” concaves, channels, steps, chines, and edges are possible alternatives in such embodiments. Other embodiments include alternative substructure formations contacting the skin at other positions between outboard left-side position 12, inboard left-side position 13, inboard right-side position 15, and outboard right-side position 16, influencing alternative bottom contour shapes.

Possible alternative shell and substructure formations are many and are customizable in fabrication, and along with the possible alternative material properties of the connected skin, affect the function and “feel” of the complete structural assembly that comprises all embodiments of the surfboard.

In all embodiments, the shell forms all rigid portions of the surfboard, and at least the deck and plan shape of the surfboard assembly. It extends longitudinally from a nose to a tail, and laterally from rail to rail, with a flat or domed or concave deck contour. In different embodiments, the shell's plan shape can be that of any long or short, traditional or alternative, conventional or side-cut, pulled or full, outline; and include any nose and tail shape. The shell's rail profiles left and right, extending out from the deck and curving downwardly to delineate some amount of rail-rocker curve along their lowermost edges and forming a thickness foil along the shell's lateral peripheries, can be hard or soft, pinched or full, with or without a release edge, and/or tucked or chine, or some combination thereof, in shape. The inboard shape of the rail profiles, which extend back upwardly towards the shell's underside within the hollow volume, can also be any combination of soft or hard shape, rounded or with an edge. The deck and its underside surfaces tend to follow a similar, though inversely shaped, lateral contour, and are thinly spaced from one another. The shell is rigidly unyielding and inflexible under localized point load, and yet is flexible when subject to larger loading forces from the user and the water, in that it has stiffly rebounding flexural and torsional properties, and will spring back to its fabricated shape when released from these forces in use.

The shell, along with the bottom contour substructure, is fabricated from any sufficiently rigid material with an adequate strength-to-weight ratio, compressive strength, and flexural characteristic. Shells are comprised of a shaped or built core, over which a sufficiently flexible and durable, corrosion and ultraviolet resistant material is laminated. Embodiments that are reductively shaped from blanks comprise core materials such as wood or polyurethane or expanded polystyrene foam or other material capable of being shaped. Glass fiber fabric or carbon fiber or other cloth permeated with a polyester or epoxy resin, is laminated to form the composite sealing structure of the shell's outer layer. In other embodiments, cloth and thermosetting resins are laminated to form the entire shell, or its inboard portions, without the use of another core material. Embodiments that are built additively from component parts also include materials such as wood or foam, as well as molded polymers or aluminum alloys. Methods of fabrication of the shell include shaping by hand or machine, computer numerical control routing, injection molding, 3D extrusion printing technologies, or other form of manufacture.

The principle function of a shell's substructure is that it operates to influence the shape of the skin from within the hollow volume, producing directionally oriented or otherwise curved formations of bottom contours at some stage of the surfboard's pneumatic adjustment or skin adaptation in use. Alternative bottom contour substructures also operate to: inform thickness foil profiles and dimensions inboard of the rail profiles; affect the flexural characteristics of the shell; restrict portions of the hollow volume accessible to a pneumatic valve at some stage of the skin's adjustment; and to limit the unrestricted surface area of the skin. Substructure formations may be fabricated as integral to the shell as part of a unified shaped construction; or be removable from it as a framework of interchangeable spars, ribs, and stringers that influence divergent bottom contour shapes in a removable and interchangeable skin.

The term “impermeable connection,” as claimed, refers to the waterproof and airtight bonding of the shell and the skin. This connection is at any point on the shell, and at the lateral peripheries of the skin. In some embodiments, the connection is a permanent chemical bond, such as epoxy or polyester resin, polyurethane or other adhesive. In other embodiments, the connection is a detachable mechanical bond, such as a continuous aluminum molding that clamps the skin to a mating surface on the shell by means of friction and set screw assemblies, or by lacing and cinching, or the like.

The hollow volume sealed between the connected shell and skin is quantifiably adjustable by means of a pneumatic valve through which the user controls the ingress or egress of air into the surfboard. The valve is comprised of any material assembly suitable for a marine environment that is capable of sealing air of sufficient positive or negative pressure in relation to the surfboard's surrounding atmospheric pressure. In some embodiments, the valve is a metal assembly, such as brass or stainless steel or aluminum. In other embodiments, the valve is a plastic assembly, such as nylon or polyvinyl chloride or other polymer. In some embodiments, the valve is operated orally; in other embodiments, the valve is operated via a separate air compressor or pump; in other embodiments, a hand operated diaphragm pump is part of the valve assembly itself. In some embodiments, pneumatic adjustments are made by the user as the surfboard is in use in the water; in other embodiments, pneumatic adjustments are made by the user on shore. Some embodiments include an additional venting valve aperture and drain plug fitted through the shell, enabling the user to control the free communication of fluids between the hollow volume and the air surrounding the surfboard.

The skin spans remote parts of the shell to which it is connected, and forms at least some portion of the surfboard's bottom surface and all of the bottom contours that are adjustable and adaptive. The skin is comprised of any sufficiently pliant material able to form smoothly to compound curves, having adequate tensile strength, weight, durability, abrasion resistance, elasticity, and impermeability or the capacity to be sealed. In some embodiments, the skin is fabricated from isotropic fabric of synthetic woven fiber, such as nylon or polyester; or organic woven fiber, such as canvas or flax; or the like. In other embodiments, the skin is fabricated from anisotropic fabric, for its directionally oriented elasticity characteristics. The fabric skin is made sufficiently water resistant and airtight with a flexible and durable, corrosion and ultraviolet resistant sealant or coating, such as urethane or latex or varnish or wax and oil blend, or like material. The sealed skin surface is smooth and durable. In other embodiments, the skin is fabricated from impermeable plastic film, rubber membrane, neoprene, sailcloth, or the like. Alternative materials and methods of skin fabrication produce different magnitudes of skin elasticity and adjustability in different embodiments.

It is the complete structural assembly of skin and shell that comprises embodiments of the surfboard, and their alternative methods of structural correlation also affect the function and “feel” of the surfboard. In some embodiments, the skin is connected to the shell with some slack; in other embodiments, the skin is stretched taut to the shell; in other embodiments, the skin is heat shrunk to the shell.

In the embodiment depicted in FIG. 1, the pliant skin and rigid shell respectively sustain a dynamic tension—compression structural correlation in their assembly. The skin is tensioned to exert rail-to-rail compressive forces on the shell to which it is connected, serving to flex and reinforce the domed deck contour; and the laterally compressed shell maintains an active tensile stress in the skin, serving to reinforce the resilience of the flat bottom contour formed when the hollow volume is of equal pressure with atmospheric. User weight and movement is transferred through the engaged shell to further dynamically tension the skin as the user flexes the deck. As the bottom contours are pneumatically modified convexly or concavely by the user, the degree of compression in the shell and the tautness that the tensioned skin retains from its counteracting forces, is altered by the hollow volume's state of positive or negative air pressure which itself reinforces the tautness of the skin.

Overall dimensions differ significantly between embodiments, depending on the type and intended use of the surfboard, ranging generally from 3′ to 12′ in length, 18″ to 30″ in width, and ¾″ to 4″ in basic unmodified thickness. Thickness dimension varies with the pneumatic adjustments of specific embodiments as well, and its scope is determined by the span of the skin both laterally and longitudinally, and its material elasticity. The range of skin travel when adjusted from maximum distension to maximum contraction is generally not more than four inches in any one embodiment, but is typically closer to one inch at maximum. Skin thickness, including any sealant, varies from about 1/32″ to 3/16″. The downward protrusion of the rail profiles and substructure formations from the shell's deck and underside typically ranges from ¾″ to 4″. The thickness of the shell between its deck and its underside, inboard of the rail profiles and from which the bottom contour substructure protrudes, typically ranges from ⅛″ to ¾″.

In the embodiment depicted in FIG. 2, a single fin box 20 is installed in the central substructure 14. The skin is adhesively joined to the proximate bottom surfaces of the substructure that house the fin box, and is cut away to enable the installation of a removable fin through it and into the fin box. Other embodiments are single fin or twin fin or other multi fin setups with fin boxes or like fin mounting systems installed into substructure formations through the skin, or into portions of the shell's underside that the skin does not span. Other embodiments have non-removable “glass-on” fins that are affixed to the skin or portions of the shell's underside that the skin does not span.

Other embodiments of the surfboard are finless, the adaptive bottom contours providing an alternative means for directional control. As the resilient skin yields to hydrodynamic forces beneath it, in consort with the rail profile shapes it contacts, it provides a directional stability to the surfboard. The skin is also responsive to the user weighting and flexing the deck above, which in some embodiments push substructure formations against the skin to reinforce and accentuate directionally oriented bottom contours that are sufficient for controlling the surfboard without a fin. 

This invention claims:
 1. A surfboard, comprising: a rigid shell, said rigid shell forming at least a longitudinally extending upper-side deck surface and an underside of said deck surface, and having a right contiguous rail profile and a left contiguous rail profile at its perimeter, and; a pliant skin, said pliant skin forming at least a portion of a bottom surface of the surfboard, and forming an adaptive bottom contour shape, and; an impermeable connection, said impermeable connection joining said rigid shell and said pliant skin to enclose a hollow volume.
 2. The surfboard of claim 1, wherein said pliant skin sustains a tensional force from spanning said underside between said right contiguous rail profile and said left contiguous rail profile, and said rigid shell sustains a compressional force from bearing said pliant skin.
 3. The surfboard of claim 1, further comprising a pneumatic valve, said pneumatic valve being disposed through said rigid shell or said pliant skin into said hollow volume, and operating to control an ingress and an egress of air, thereby adjusting said adaptive bottom contour shape.
 4. The surfboard of claim 1, further comprising a pneumatic valve, said pneumatic valve being disposed through said rigid shell or said pliant skin into said hollow volume, and operating to control an ingress and an egress of air, thereby adjusting said surfboard's volume.
 5. The surfboard of claim 3, further comprising a bottom contour substructure integral to said rigid shell, said bottom contour substructure protruding downwardly from said underside through said hollow volume, and operating to influence said adaptive bottom contour shape, wherein said impermeable connection is a chemical bond.
 6. The surfboard of claim 3, further comprising a bottom contour substructure separable from said rigid shell, said bottom contour substructure protruding downwardly from said under-side through said hollow volume, and operating to influence said adaptive bottom contour shape, wherein said impermeable connection is a detachable mechanical bond.
 7. A surfboard, comprising: a rigid shell, said rigid shell forming at least a longitudinally extending upper-side deck surface and an inverse under-side of said deck surface, and having a contiguous rail profile at its perimeter, and; a pliant skin, said pliant skin forming at least a portion of a bottom surface of the surfboard, and forming an adaptive bottom contour shape, and; an impermeable connection, said impermeable connection joining said rigid shell and said pliant skin to enclose a hollow volume, and; a pneumatic valve, said pneumatic valve being disposed through said rigid shell or said pliant skin into said hollow volume, and operating to control an ingress and an egress of air, thereby adjusting said adaptive bottom contour shape and the volume dimension of said surfboard, and; said rigid shell also comprising a bottom contour substructure protruding downwardly from said under-side through said hollow volume, and operating to influence said adaptive bottom contour shape.
 8. A process for adjusting surfboard bottom contours to a plurality of shapes, which comprises the alternative steps of: a) temporarily unsealing and controlling the ingress of air into a hollow volume enclosed between a rigid shell that forms at least the deck and rails of the surfboard, and a pliant skin that forms a portion of the bottom surface of the surfboard, before resealing the hollow volume by means of a pneumatic valve disposed through the rigid shell or said pliant skin, thereby distending the pliant skin away from the under-side of the deck, producing a convex bottom contour; or b) temporarily unsealing and controlling the egress of air from a volume enclosed between a rigid shell that forms at least the deck and rails of the surfboard, and a pliant skin that forms a portion of the bottom surface of the surfboard, before resealing the hollow volume by means of a pneumatic valve disposed through the rigid shell or said pliant skin, thereby contracting the pliant skin towards the underside of the deck, producing a concave bottom contour; or c) temporarily unsealing and facilitating the free communication of air enclosed between a rigid shell that forms at least the deck and rails of the surfboard, and a pliant skin that forms a portion of the bottom surface of the surfboard, with the surrounding air before resealing the hollow volume by means of a pneumatic valve disposed through the rigid shell or said pliant skin, producing a flat bottom contour. 